Polypropylene for Reduced Plate Out in Polymer Article Production Processes

ABSTRACT

Polymer articles and processes of forming polymer articles are described herein. The processes generally include providing a propylene based polymer formed from a metallocene catalyst and melt processing the propylene based polymer to form a polymer article.

FIELD

Embodiments of the present invention generally relate to propylenepolymers. Specifically, embodiments of the present invention relate topropylene polymers that reduce the occurrence of plate-out on moldedplastic parts.

BACKGROUND

“Plate-out” is an objectionable coating that may gradually form onsurfaces, such as metal surfaces, of molds during processing ofplastics. This coating can cause haziness and cloudiness in the moldedplastic parts. The problem of plate-out can be exacerbated due tomigration of additives to the polymer/metal interface during processing.Bloom, also known as migration, can result in cloudiness of the moldedplastic part.

Therefore, a need exists for polymers and/or processes that minimizeplate-out or bloom in molded plastic parts.

SUMMARY

Embodiments of the present invention include polymer articles andprocesses of forming polymer articles. In one or more embodiments, theprocesses generally include providing a propylene based polymer formedfrom a metallocene catalyst, melt processing the propylene based polymerto form a polymer article, wherein the process is capable of operationfor at least about 30 hours at a barrel temperature of at least 420° F.and a hot runner temperature of 480° F. without experiencing plate-out.

In another embodiment, the processes include providing a propylene basedrandom polymer formed from a metallocene catalyst, wherein the propylenebased random copolymer includes from about 0.5 wt. % ethylene andexhibits a melt flow rate of from about 15 dg/min. to about 100 dg/min.,melt processing the propylene based polymer to form a polymer articleand heat treating the polymer article, wherein the polymer articleexhibits a reduction in haze upon heat treatment.

DETAILED DESCRIPTION Introduction and Definitions

A detailed description will now be provided. Each of the appended claimsdefines a separate invention, which for infringement purposes isrecognized as including equivalents to the various elements orlimitations specified in the claims. Depending on the context, allreferences below to the “invention” may in some cases refer to certainspecific embodiments only. In other cases it will be recognized thatreferences to the “invention” will refer to subject matter recited inone or more, but not necessarily all, of the claims. Each of theinventions will now be described in greater detail below, includingspecific embodiments, versions and examples, but the inventions are notlimited to these embodiments, versions or examples, which are includedto enable a person having ordinary skill in the art to make and use theinventions when the information in this patent is combined withavailable information and technology.

Various terms as used herein are shown below. To the extent a term usedin a claim is not defined below, it should be given the broadestdefinition persons in the pertinent art have given that term asreflected in printed publications and issued patents at the time offiling. Further, unless otherwise specified, all compounds describedherein may be substituted or unsubstituted and the listing of compoundsincludes derivatives thereof.

Various ranges are further recited below. It should be recognized thatunless stated otherwise, it is intended that the endpoints are to beinterchangeable. Further, any point within that range is contemplated asbeing disclosed herein.

Catalyst Systems

Catalyst systems useful for polymerizing olefin monomers include anycatalyst system known to one skilled in the art. For example, thecatalyst system may include metallocene catalyst systems, single sitecatalyst systems, Ziegler-Natta catalyst systems or combinationsthereof, for example. A brief discussion of such catalyst systems isincluded below, but is in no way intended to limit the scope of theinvention to such catalysts.

Metallocene catalysts may be characterized generally as coordinationcompounds incorporating one or more cyclopentadienyl (Cp) groups (whichmay be substituted or unsubstituted, each substitution being the same ordifferent) coordinated with a transition metal.

The substituent groups on Cp may be linear, branched or cyclichydrocarbyl radicals, for example. The inclusion of cyclic hydrocarbylradicals may transform the Cp into other contiguous ring structures,such as indenyl, azulenyl and fluorenyl groups, for example. Thesecontiguous ring structures may also be substituted or unsubstituted byhydrocarbyl radicals, such as C₁ to C₂₀ hydrocarbyl radicals, forexample.

A specific, non-limiting, example of a metallocene catalyst is a bulkyligand metallocene compound generally represented by the formula:

[L]_(m)M[A]_(n);

wherein L is a bulky ligand, A is a leaving group, M is a transitionmetal and m and n are such that the total ligand valency corresponds tothe transition metal valency. For example m may be from 1 to 4 and n maybe from 0 to 3.

The metal atom “M” of the metallocene catalyst compound, as describedthroughout the specification and claims, may be selected from Groups 3through 12 atoms and lanthanide Group atoms, or from Groups 3 through 10atoms or from Sc, Ti, Zr, Hf, V, Nb, Ta, Mn, Re, Fe, Ru, Os, Co, Rh, Irand Ni. The oxidation state of the metal atom “M” may range from 0 to +7or is +1, +2, +3, +4 or +5, for example.

The bulky ligand generally includes a cyclopentadienyl group (Cp) or aderivative thereof. The Cp ligand(s) form at least one chemical bondwith the metal atom M to form the “metallocene catalyst.” The Cp ligandsare distinct from the leaving groups bound to the catalyst compound inthat they are not as highly susceptible to substitution/abstractionreactions as the leaving groups.

Cp ligands may include ring(s) or ring system(s) including atomsselected from group 13 to 16 atoms, such as carbon, nitrogen, oxygen,silicon, sulfur, phosphorous, germanium, boron, aluminum andcombinations thereof, wherein carbon makes up at least 50% of the ringmembers. Non-limiting examples of the ring or ring systems includecyclopentadienyl, cyclopentaphenanthreneyl, indenyl, benzindenyl,fluorenyl, tetrahydroindenyl, octahydrofluorenyl, cyclooctatetraenyl,cyclopentacyclododecene, 3,4-benzofluorenyl, 9-phenylfluorenyl,8-H-cyclopent[a]acenaphthylenyl, 7-H-dibenzofluorenyl,indeno[1,2-9]anthrene, thiophenoindenyl, thiophenofluorenyl,hydrogenated versions thereof (e.g., 4,5,6,7-tetrahydroindenyl or“H₄Ind”), substituted versions thereof and heterocyclic versionsthereof, for example.

Cp substituent groups may include hydrogen radicals, alkyls (e.g.,methyl, ethyl, propyl, butyl, pentyl, hexyl, fluoromethyl, fluoroethyl,difluoroethyl, iodopropyl, bromohexyl, benzyl, phenyl, methylphenyl,tert-butylphenyl, chlorobenzyl, dimethylphosphine andmethylphenylphosphine), alkenyls (e.g., 3-butenyl, 2-propenyl and5-hexenyl), alkynyls, cycloalkyls (e.g, cyclopentyl and cyclohexyl),aryls, alkoxys (e.g., methoxy, ethoxy, propoxy and phenoxy), aryloxys,alkylthiols, dialkylamines (e.g., dimethylamine and diphenylamine),alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbamoyls, alkyl- anddialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, organometalloidradicals (e.g., dimethylboron), Group 15 and Group 16 radicals (e.g.,methylsulfide and ethylsulfide) and combinations thereof, for example.In one embodiment, at least two substituent groups, two adjacentsubstituent groups in one embodiment, are joined to form a ringstructure.

Each leaving group “A” is independently selected and may include anyionic leaving group, such as halogens (e.g., chloride and fluoride),hydrides, C₁ to C₁₂ alkyls (e.g., methyl, ethyl, propyl, phenyl,cyclobutyl, cyclohexyl, heptyl, tolyl, trifluoromethyl, methylphenyl,dimethylphenyl and trimethylphenyl), C₂ to C₁₂ alkenyls (e.g., C₂ to C₆fluoroalkenyls), C₆ to C₁₂ aryls (e.g., C₇ to C₂₀ alkylaryls), C₁ to C₁₂alkoxys (e.g., phenoxy, methyoxy, ethyoxy, propoxy and benzoxy), C₆ toC₁₆ aryloxys, C₇ to C₁₈ alkylaryloxys and C₁ to C₁₂heteroatom-containing hydrocarbons and substituted derivatives thereof,for example.

Other non-limiting examples of leaving groups include amines,phosphines, ethers, carboxylates (e.g., C₁ to C₆ alkylcarboxylates, C₆to C₁₂ arylcarboxylates and C₇ to C₁₈ alkylarylcarboxylates), dienes,alkenes, hydrocarbon radicals having from 1 to 20 carbon atoms (e.g.,pentafluorophenyl) and combinations thereof, for example. In oneembodiment, two or more leaving groups form a part of a fused ring orring system.

In a specific embodiment, L and A may be bridged to one another to forma bridged metallocene catalyst. A bridged metallocene catalyst, forexample, may be described by the general formula:

XCp^(A)Cp^(B)MA_(n);

wherein X is a structural bridge, CP^(A) and Cp^(B) each denote acyclopentadienyl group or derivatives thereof, each being the same ordifferent and which may be either substituted or unsubstituted, M is atransition metal and A is an alkyl, hydrocarbyl or halogen group and nis an integer between 0 and 4, and either 1 or 2 in a particularembodiment.

Non-limiting examples of bridging groups “X” include divalenthydrocarbon groups containing at least one Group 13 to 16 atom, such as,but not limited to, at least one of a carbon, oxygen, nitrogen, silicon,aluminum, boron, germanium, tin and combinations thereof, wherein theheteroatom may also be a C₁ to C₁₂ alkyl or aryl group substituted tosatisfy a neutral valency. The bridging group may also containsubstituent groups as defined above including halogen radicals and iron.More particular non-limiting examples of bridging group are representedby C₁ to C₆ alkylenes, substituted C₁ to C₆ alkylenes, oxygen, sulfur,R₂C═, R₂Si═, —Si(R)₂Si(R₂)—, R₂Ge═ or RP═ (wherein “═” represents twochemical bonds), where R is independently selected from hydrides,hydrocarbyls, halocarbyls, hydrocarbyl-substituted organometalloids,halocarbyl-substituted organometalloids, disubstituted boron atoms,disubstituted Group 15 atoms, substituted Group 16 atoms and halogenradicals, for example. In one embodiment, the bridged metallocenecatalyst component has two or more bridging groups.

Other non-limiting examples of bridging groups include methylene,ethylene, ethylidene, propylidene, isopropylidene, diphenylmethylene,1,2-dimethylethylene, 1,2-diphenylethylene, 1,1,2,2-tetramethylethylene,dimethylsilyl, diethylsilyl, methyl-ethylsilyl,trifluoromethylbutylsilyl, bis(trifluoromethyl)silyl, di(n-butyl)silyl,di(n-propyl)silyl, di(i-propyl) silyl, di(n-hexyl)silyl,dicyclohexylsilyl, diphenylsilyl, cyclohexylphenylsilyl,t-butylcyclohexylsilyl, di(t-butylphenyl)silyl, di(p-tolyl)silyl and thecorresponding moieties, wherein the Si atom is replaced by a Ge or a Catom; dimethylsilyl, diethylsilyl, dimethylgermyl and/or diethylgermyl.

In another embodiment, the bridging group may also be cyclic and include4 to 10 ring members or 5 to 7 ring members, for example. The ringmembers may be selected from the elements mentioned above and/or fromone or more of boron, carbon, silicon, germanium, nitrogen and oxygen,for example. Non-limiting examples of ring structures which may bepresent as or part of the bridging moiety are cyclobutylidene,cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclooctylidene,for example. The cyclic bridging groups may be saturated or unsaturatedand/or carry one or more substituents and/or be fused to one or moreother ring structures. The one or more Cp groups which the above cyclicbridging moieties may optionally be fused to may be saturated orunsaturated. Moreover, these ring structures may themselves be fused,such as, for example, in the case of a naphthyl group.

In one embodiment, the metallocene catalyst includes CpFlu Typecatalysts (e.g., a metallocene catalyst wherein the ligand includes a Cpfluorenyl ligand structure) represented by the following formula:

X(CpR¹ _(n)R² _(m))(FIR³ _(p));

wherein Cp is a cyclopentadienyl group or derivatives thereof, Fl is afluorenyl group, X is a structural bridge between Cp and Fl, R¹ is anoptional substituent on the Cp, n is 1 or 2, R² is an optionalsubstituent on the Cp bound to a carbon immediately adjacent to the ipsocarbon, m is 1 or 2 and each R³ is optional, may be the same ordifferent and may be selected from C₁ to C₂₀ hydrocarbyls. In oneembodiment, p is selected from 2 or 4. In one embodiment, at least oneR³ is substituted in either the 2 or 7 position on the fluorenyl groupand at least one other R³ being substituted at an opposed 2 or 7position on the fluorenyl group.

In yet another aspect, the metallocene catalyst includes bridgedmono-ligand metallocene compounds (e.g., mono cyclopentadienyl catalystcomponents). In this embodiment, the metallocene catalyst is a bridged“half-sandwich” metallocene catalyst. In yet another aspect of theinvention, the at least one metallocene catalyst component is anunbridged “half sandwich” metallocene. (See, U.S. Pat. No. 6,069,213,U.S. Pat. No. 5,026,798, U.S. Pat. No. 5,703,187, U.S. Pat. No.5,747,406, U.S. Pat. No. 5,026,798 and U.S. Pat. No. 6,069,213, whichare incorporated by reference herein.)

Non-limiting examples of metallocene catalyst components consistent withthe description herein include, for examplecyclopentadienylzirconiumA_(n); indenylzirconiumA_(n);(1-methylindenyl)zirconiumA_(n); (2-methylindenyl)zirconiumA_(n),(1-propylindenyl)zirconiumA_(n); (2-propylindenyl)zirconiumA_(n);(1-butylindenyl)zirconiumA_(n); (2-butylindenyl)zirconiumA_(n);methylcyclopentadienylzirconiumA_(n); tetrahydroindenylzirconiumA_(n):pentamethylcyclopentadienylzirconiumA_(n);cyclopentadienylzirconiumA_(n);pentamethylcyclopentadienyltitaniumA_(n);tetramethylcyclopentyltitaniumA_(n);(1,2,4-trimethylcyclopentadienyl)zirconiumA_(n);dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(cyclopentadienyl)zirconiumA_(n);dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2,3-trimethylcyclopentadienyl)zirconiumA_(n);dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2-dimethylcyclopentadienyl)zirconiumA_(n);dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(2-methylcyclopentadienyl)zirconiumA_(n);dimethylsilylcyclopentadienylindenylzirconiumA_(n);dimethylsilyl(2-methylindenyl)(fluorenyl)zirconiumA_(n);diphenylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(3-propylcyclopentadienyl)zirconiumA_(n);dimethylsilyl (1,2,3,4-tetramethylcyclopentadienyl)(3-t-butylcyclopentadienyl)zirconiumA_(n); dimethylgermyl(1,2-dimethylcyclopentadienyl)(3-isopropylcyclopentadienyl)zirconiumA_(n);dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(3-methylcyclopentadienyl)zirconiumA_(n);diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconiurnA_(n);diphenylmethylidenecyclopentadienylindenylzirconiumA_(n);isopropylidenebiscyclopentadienylzirconiumA_(n);isopropylidene(cyclopentadienyl)(9-fluorenyl)zirconiumA_(n);isopropylidene(3-methylcyclopentadienyl)(9-fluorenyl)zirconiumA_(n);ethylenebis(9-fluorenyl)zirconiumA_(n);ethylenebis(1-indenyl)zirconiumA_(n);ethylenebis(1-indenyl)zirconiumA_(n);ethylenebis(2-methyl-1-indenyl)zirconiumA_(n);ethylenebis(2-methyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);ethylenebis(2-propyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);ethylenebis(2-isopropyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);ethylenebis(2-butyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);ethylenebis(2-isobutyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);dimethylsilyl(4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);diphenyl(4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconiumA_(n);dimethylsilylbis(cyclopentadienyl)zirconiumA_(n);dimethylsilylbis(9-fluorenyl)zirconiumA_(n);dimethylsilylbis(1-indenyl)zirconiumA_(n);dimethylsilylbis(2-methylindenyl)zirconiumA_(n);dimethylsilylbis(2-propylindenyl)zirconiumA_(n);dimethylsilylbis(2-butylindenyl)zirconiumA_(n);diphenylsilylbis(2-methylindenyl)zirconiumA_(n);diphenylsilylbis(2-propylindenyl)zirconiumA_(n);diphenylsilylbis(2-butylindenyl)zirconiumA_(n);dimethylgermylbis(2-methylindenyl)zirconiumA_(n);dimethylsilylbistetrahydroindenylzirconiumA_(n);dimethylsilylbistetramethylcyclopentadienylzirconiumA_(n);dimethylsily(cyclopentadienyl)(9-fluorenyl)zirconiumA_(n);diphenylsilyl(cyclopentadienyl)(9-fluorenyl)zirconiumA_(n);diphenylsilylbisindenylzirconiumA_(n);cyclotrimethylenesilyltetramethylcyclopentadienylcyclopentadienylzirconiumA_(n);cyclotetramethylenesilyltetramethylcyclopentadienylcyclopentadienylzirconiumA_(n);cyclotrimethylenesilyl(tetranethylcyclopentadienyl)(2-methylindenyl)zirconiumA_(n);cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(3-methylcyclopentadienyl)zirconiumA_(n);cyclotrimethylenesilylbis(2-methylindenyl)zirconiumA_(n);cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2,3,5-trimethylclopentadienyl)zirconiumA_(n);cyclotrimethylenesilylbis(tetramethylcyclopentadienyl)zirconiumA_(n);dimethylsilyl(tetramethylcyclopentadieneyl)(N-tertbutylamido)titaniumA_(n);biscyclopentadienylchromiumA_(n); biscyclopentadienylzirconiumA_(n);bis(n-butylcyclopentadienyl)zirconiumA_(n);bis(n-dodecyclcyclopentadienyl)zirconiumA_(n);bisethylcyclopentadienylzirconiumA_(n);bisisobutylcyclopentadienylzirconiumA_(n);bisisopropylcyclopentadienylzirconiumA_(n);bismethylcyclopentadienylzirconiumA_(n);bisoctylcyclopentadienylzirconiumA_(n);bis(n-pentylcyclopentadienyl)zirconiumA_(n);bis(n-propylcyclopentadienyl)zirconiumA_(n);bistrimethylsilylcyclopentadienylzirconiumA_(n);bis(1,3-bis(trimethylsilyl)cyclopentadienyl)zirconiumA_(n);bis(1-ethyl-2-methylcyclopentadienyl)zirconiumA_(n);bis(1-ethyl-3-methylcyclopentadienyl)zirconiumA_(n);bispentamethylcyclopentadienylzirconiumA_(n);bispentamethylcyclopentadienylzirconiumA_(n);bis(1-propyl-3-methylcyclopentadienyl)zirconiumA_(n);bis(1-n-butyl-3-methylcyclopentadienyl)zirconiumA_(n);bis(1-isobutyl-3-methylcyclopentadienyl)zirconiumA_(n);bis(1-propyl-3-butylcyclopentadienyl)zirconiumA_(n);bis(1,3-n-butylcyclopentadienyl)zirconiumA_(n);bis(4,7-dimethylindenyl)zirconiumA_(n); bisindenylzirconiumA_(n);bis(2-methylindenyl)zirconiumA_(n);cyclopentadienylindenylzirconiumA_(n);bis(n-propylcyclopentadienyl)hafniumA_(n);bis(n-butylcyclopentadienyl)hafniumA_(n);bis(n-pentylcyclopentadienyl)hafniumA_(n);(n-propylcyclopentadienyl)(n-butylcyclopentadienyl)hafniumA_(n);bis[(2-trimethylsilylethyl)cyclopentadienyl]hafniumA_(n);bis(trimethylsilylcyclopentadienyl)hafniumA_(n);bis(2-n-propylindenyl)hafniumA_(n); bis(2-n-butylindenyl)hafniumA_(n);dimethylsilylbis(n-propylcyclopentadienyl) hafniumA_(n);dimethylsilylbis(n-butylcyclopentadienyl)hafniumA_(n);bis(9-n-propylfluorenyl)hafniumA_(n);bis(9-n-butylfluorenyl)hafniumA_(n);(9-n-propylfluorenyl)(2-n-propylindenyl)hafniumA_(n);bis(1-n-propyl-2-methylcyclopentadienyl)hafniumA_(n);(n-propylcyclopentadienyl)(1-n-propyl-3-n-butylcyclopentadienyl)hafniumA_(n);dimethylsilyltetramethylcyclopentadienylcyclopropylamidotitaniumA_(n);dimethylsilyltetramethyleyclopentadienylcyclobutylamidotitaniumA_(n);dimethylsilyltetramethyleyclopentadienylcyclopentylamidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienylcyclohexylamnidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienylcycloheptylamidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienylcyclooctylamidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienylcyclononylamidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienylcyclodecylamidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienylcycloundecylamidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienylcyclododecylamidotitaniumA_(n);dimethylsilyltetramethylcyclopentadienyl(sec-butylamido)titaniumA_(n);dimethylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titaniumA_(n);dimethylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titaniumA_(n);dimethylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titaniumA_(n);dimethylsilylbis(cyclopentadienyl)zirconiumA_(n);dimethylsilylbis(tetramethylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(methylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(dimethylcyclopentadienyl)zirconiumA_(n);dimethylsilyl(2,4-dimethylcyclopentadienyl)(3′,5′-dimethylcyclopentadienyl)zirconiumA_(n);dimethylsilyl(2,3,5-trimethylcyclopentadienyl)(2′,4′,5′-dimethylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(t-butylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(trimethylsilylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(2-trimethylsilyl-4-t-butylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(4,5,6,7-tetrahydro-indenyl)zirconiumA_(n);dimethylsilylbis(indenyl)zirconiumA_(n);dimethylsilylbis(2-methylindenyl)zirconiumA_(n);dimethylsilylbis(2,4-dimethylindenyl)zirconiumA_(n);dimethylsilylbis(2,4,7-trimethylindenyl)zirconiumA_(n);dimethylsilylbis(2-methyl-4-phenylindenyl)zirconiumA_(n);dimethylsilylbis(2-ethyl-4-phenylindenyl)zirconiurnA_(n);dimethylsilylbis(benz[e]indenyl)zirconiumA_(n);dimethylsilylbis(2-methylbenz[e]indenyl)zirconiumA_(n);dimethylsilylbis(benz[f]indenyl)zirconiumA_(n);dimethylsilylbis(2-methylbenz[f]indenyl)zirconiumA_(n);dimethylsilylbis(3-methylbenz[f]indenyl)zirconiumA_(n);dimethylsilylbis(cyclopenta[cd]indenyl)zirconiumA_(n);dimethylsilylbis(cyclopentadienyl)zirconiumA_(n);dimethylsilylbis(tetramethylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(methylcyclopentadienyl)zirconiumA_(n);dimethylsilylbis(dimethylcyclopentadienyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-fluorenyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-indenyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-2,7-di-t-butylfluorenyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-3-methyl fluorenyl)zirconiumA_(n);isoropylidene(cyclopentadienyl-4-methylfluorenyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-octahydrofluorenyl)zirconiumA_(n);isopropylidene(methylcyclopentadienyl-fluorenyl)zirconiumA_(n);isopropylidene(dimethyicyclopentadienylfluorenyl)zirconiumA_(n);isopropylidenc(tetramethylcyclopentadienyl-fluorenyl)zirconiumA_(n);diphenylmethylene(cyclopentadienyl-fluorenyl)zirconiumA_(n);diphenylmethylene(cyclopentadienyl-indenyl)zirconiumA_(n);diphenylmethylene(cyclopentadienyl-2,7-di-t-butylfluorenyl)zirconiumA_(n);diphenylmethylene(cyclopentadienyl-3-methylfluorenyl)zirconiumA_(n);diphenylmethylene(cyclopentadienyl-4-methylfluorenyl)zirconiumA_(n);diphenyimethylene(cyclopentadienyloctahydrofluorenyl)zirconiumA_(n);diphenylmethylene(methylcyclopentadienyl-fluorenyl)zirconiumA_(n);diphenylmethylene(dimethylcyclopentadienyl-fluorenyl)zirconiumA_(n);diphenylmethylene(tetramethylcyclopentadienyl-fluorenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienyl-fluorenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienylindenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienyl-2,7-di-t-butylfluorenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienyl-3-methylfluorenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienyl-4-methylfluorenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienyloctahydrofluorenyl)zirconiumA_(n);cyclohexylidene(methylcyclopentadienylfluorenyl)zirconiumA_(n);cyclohexylidene(dimethylcyclopentadienyl-fluorenyl)zirconiumA_(n);cyclohexylidene(tetramethylcyclopentadienylfluorenyl)zirconiumA_(n);dimethylsilyl(cyclopentadienyl-fluorenyl)zirconiumA_(n);dimethylsilyl(cyclopentadienyl-indenyl)zirconiumA_(n);dimethylsilyl(cyclopentdienyl-2,7-di-t-butylfluorenyl)zirconiumA_(n);dimethylsilyl(cyclopentadienyl-3-methylfluorenyl)zirconiumA_(n);dimethylsilyl(cyclopentadienyl-4-methylfluorenyl)zirconiunA_(n);dimethylsilyl(cyclopentadienyl-octahydrofluorenyl)zirconiumA_(n);dimethylsilyl(methylcyclopentanedienyl-fluorenyl)zirconiumA_(n);dimethylsilyl(dimethylcyclopentadienylfluorenyl)zirconiumA_(n);dimethylsilyl(tetramethylcyclopentadienylfluorenyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-fluorenyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-indenyl)zirconiumA_(n);isopropylidene(cyclopentadienyl-2,7-di-t-butylfluorenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienylfluorenyl)zirconiumA_(n);cyclohexylidene(cyclopentadienyl-2,7-di-t-butylfluorenyl)zirconiumA_(n);dimethylsilyl(cyclopentadienylfluorenyl)zirconiumA_(n);methylphenylsilyltetramethylcyclopentadienylcyclopropylamidotitaniumA_(n);methylphenylsilyltetramethylcyclopentadienylcyclobutylamidotitaniumA_(n);methytphenyisilyltetramethylcyclopentadienylcyclopentylamidotitaniumA_(n);methylphenyisilyltetramethylcyclopentadienylcyclohexylamidotitaniumA_(n);methylphenylsilyitetramethylcyclopentadienylcycloheptylamidotitaniumA_(n);methylplienyisilyltetramethylcyclopentadienylcyclooctylamidotitaniumA_(n);methylphenylsilyltetramethylcyclopentadienylcyclononylamidotitaniumA_(n);methylphenyisilyltetramethyleyclopentadienylcyclodecylamidotitaniumA_(n);methylphenylsilyltetramethylcyclopentadienylcycloundecylamidotitaniumA_(n);methylphenylsilyltetramethylcyclopentadienylcyclododecylamidotitaniumA_(n);methylphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titaniumA_(n);methylphenyisilyl(tetramethylcyclopentadienyl)(n-octylamido)titaniumA_(n);methylphenylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titaniuimA_(n);methylphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titaniumA_(n);diphenylsilyltetramethylcyclopentadienylcyclopropylamidotitaniumA_(n);diphenylsilyltetramethylcyclopentadienylcyclobutylamidotitaniumA_(n);diphenylsilyltetramethylcyclopentadienylcyclopentylamidotitaniumA_(n);diphenylsilyltetramethylcyclopentadienylcyclohexylamidotitaniumA_(n);diphenylsilyltetramethylcyclopentadienylcycloheptylamidotitaniumA_(n)diphenyisilyltetramethylcyclopentadienylcyclooctylamidotitaniumA_(n);diphenylsilyltetramethylcyclopentadienylcyclononylamidotitaniunA_(n);diphenyisilyltetramethylcyclopentadienylcyclodecylamidotitaniumA_(n);diphenyisilyltetramethylcyclopentadienylcycloundecylamnidotitaniumnA_(n);diphenylsilyltetramethylcyclopentadienylcyclododecylamidotitaniumA_(n);diphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titaniumA_(n);diphenylsily(tetraniethylcyclopentadienyl)(n-octylamido)titaniumA_(n);diphenylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titaniumA_(n);anddiphenyisilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titaniumA_(n).

The metallocene catalysts may be activated with a metallocene activatorfor subsequent polymerization. As used herein,.the term “metalloceneactivator” is defined to be any compound or combination of compounds,supported or unsupported, which may activate a single-site catalystcompound (e.g., metallocenes, Group 15 containing catalysts, etc.) Thismay involve the abstraction of at least one leaving group (A group inthe formulas/structures above, for example) from the metal center of thecatalyst component. The metallocene catalysts are thus activated towardsolefin polymerization using such activators.

Embodiments Of such activators include Lewis acids, such as cyclic oroligomeric polyhydrocarbylaluminum oxides, non-coordinating ionicactivators (NCA), ionizing activators, stoichiometric activators,combinations thereof or any other compound that may convert a neutralmetallocene catalyst component to a metallocene cation that is activewith respect to olefin polymerization.

The Lewis acids may include alumoxane (e.g., “MAO”), modified alumoxane(e.g., “TIBAO”) and alkylaluminum compounds, for example. Non-limitingexamples of aluminum alkyl compounds may include trimethylaluminum,triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum andtri-n-octylaluminum, for example.

Ionizing activators are well known in the art and are described by, forexample, Eugene You-Xian Chen & Tobin J. Marks, Cocatalysts forMetal-Catalyzed Olefin Polymerization: Activators, Activation Processes,and Structure-Activity Relationships 100(4) CHEMICAL REVIEWS 1391-1434(2000). Examples of neutral ionizing activators include Group 13tri-substituted compounds, in particular, tri-substituted boron,tellurium, aluminum, gallium and indium compounds and mixtures thereof(e.g., trisperfluorophenyl boron metalloid precursors), for example. Thesubstituent groups may be independently selected from alkyls, alkenyls,halogen, substituted alkyls, aryls, arylhalides, alkoxy and halides, forexample. In one embodiment, the three groups are independently selectedfrom halogens, mono or multicyclic (including halosubstituted) aryls,alkyls, alkenyl compounds and mixtures thereof, for example. In anotherembodiment, the three groups are selected from C₁ to C₂₀ alkenyls, C₁ toC₂₀ alkyls, C₁ to C₂₀ alkoxys, C₃ to C₂₀ aryls and combinations thereof,for example. In yet another embodiment, the three groups are selectedfrom the group highly halogenated C₁ to C₄ alkyls, highly halogenatedphenyls, and highly halogenated naphthyls and mixtures thereof, forexample. By “highly halogenated”, it is meant that at least 50% of thehydrogens are replaced by a halogen group selected from fluorine,chlorine and bromine.

Illustrative, not limiting examples of ionic ionizing activators includetrialkyl-substituted ammonium salts (e.g.,triethylammoniumtetraphenylborate, tripropylammoniumtetraphenylborate,tri(n-butyl)ammoniumtetraphenylborate,trimethylammoniumtetra(p-tolyl)borate,trimethylammoniumtetra(o-tolyl)borate,tributylammoniumtetra(pentafluorophenyl)borate,tripropylammoniumtetra(o,p-dimethylphenyl)borate,tributylammoniumtetra(m,m-dimethylphenyl)borate,tributylammoniumtetra(p-tri-fluoromethylphenyl)borate,tributylammoniumtetra(pentafluorophenyl)borate andtri(n-butyl)ammoniumtetra(o-tolyl)borate), N,N-dialkylanilinium salts(e.g., N,N-dimethylaniliniumtetraphenylborate,N,N-diethylaniliniumtetraphenylborate) andN,N-2,4,6-pentamethylaniliniumtetraphenylborate), dialkyl ammonium salts(e.g., diisopropylammoniumtetrapentafluorophenylborate anddicyclohexylammoniumtetraphenylborate), triaryl phosphonium salts (e.g.,triphenylphosphoniumtetraphenylborate,trimethylphenylphosphoniumtetraphenylborate andtridimethylphenylphosphoniumtetraphenylborate) and their aluminumequivalents, for example.

In yet another embodiment, an alkylaluminum compound may be used inconjunction with a heterocyclic compound. The ring of the heterocycliccompound may include at least one nitrogen, oxygen, and/or sulfur atom,and includes at least one nitrogen atom in one embodiment. Theheterocyclic compound includes 4 or more ring members in one embodiment,and 5 or more ring members in another embodiment, for example.

The heterocyclic compound for use as an activator with an alkylaluminumcompound may be unsubstituted or substituted with one or a combinationof substituent groups. Examples of suitable substituents includehalogens, alkyls, alkenyls or alkynyl radicals, cycloalkyl radicals,aryl radicals, aryl substituted alkyl radicals, acyl radicals, aroylradicals, alkoxy radicals, aryloxy radicals, alkylthio radicals,dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonylradicals, carbomoyl radicals, alkyl- or dialkyl-carbamoyl radicals,acyloxy radicals, acylamino radicals, aroylamino radicals, straight,branched or cyclic, alkylene radicals or any combination thereof, forexample.

Non-limiting examples of hydrocarbon substituents include methyl, ethyl,propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl, phenyl,fluoromethyl, fluoroethyl, difluoroethyl, iodopropyl, bromohexyl orchlorobenzyl, for example.

Non-limiting examples of heterocyclic compounds utilized includesubstituted and unsubstituted pyrroles, imidazoles, pyrazoles,pyrrolines, pyrrolidines, purines, carbazoles, indoles, phenyl indoles,2,5-dimethylpyrroles, 3-pentafluorophenylpyrrole,4,5,6,7-tetrafluoroindole or 3,4-difluoropyrroles, for example.

Combinations of activators are also contemplated by the invention, forexample, alumoxanes and ionizing activators in combinations. Otheractivators include aluminum/boron complexes, perchlorates, periodatesand iodates including their hydrates, lithium(2,2′-bisphenyl-ditrimethylsilicate)-4T-HF and silylium salts incombination with a non-coordinating compatible anion, for example. Inaddition to the compounds listed above, methods of activation, such asusing radiation and electro-chemical oxidation are also contemplated asactivating methods for the purposes of enhancing the activity and/orproductivity of a single-site catalyst compound, for example. (.See,U.S. Pat. No. 5,849,852, U.S. Pat. No. 5,859,653, U.S. Pat. No.5,869,723 and WO 98/32775.)

The catalyst may be activated in any manner known to one skilled in theart. For example, the catalyst and activator may be combined in molarratios of activator to catalyst of from 1000:1 to 0.1:1, or from 500:1to 1:1, or from about 100:1 to about 250:1, or from 150:1 to 1:1, orfrom 50:1 to 1:1, or from 10:1 to 0.5:1 or from 3:1 to 0.3:1, forexample.

The activators may or may not be associated with or bound to a support,either in association with the catalyst (e.g., metallocene) or separatefrom the catalyst component, such as described by Gregory G. Heathy,Heterogeneous Single-Site Catalysts for Olefin Polymerization 100(4)CHEMICAL REVIEWS 1347-1374 (2000).

Metallocene Catalysts may be supported or unsupported. Typical supportmaterials may include talc, inorganic oxides, clays and clay minerals,ion-exchanged layered compounds, diatomaceous earth compounds, zeolitesor a resinous support material, such as a polyolefin, for example.

Specific inorganic oxides include silica, alumina, magnesia, titania andzirconia, for example. The inorganic oxides used as support materialsmay have an average particle size of from 5 microns to 600 microns orfrom 10 microns to 100 microns, a surface area of from 50 m²/g to 1,000m²/g or from 100 m²/g to 400 m²/g and a pore volume of from 0.5 cc/g to3.5 cc/g or from 0.5 cc/g to 2.5 cc/g, for example.

Methods for supporting metallocene catalysts are generally known in theart. (See, U.S. Pat. No. 5,643,847, which is incorporated by referenceherein.)

Optionally, the support material, the catalyst component, the catalystsystem or combinations thereof, may be contacted with one or morescavenging compounds prior to or during polymerization. The term“scavenging compounds” is meant to include those compounds effective forremoving impurities (e.g., polar impurities) from the subsequentpolymerization reaction environment. Impurities may be inadvertentlyintroduced with any of the polymerization reaction components,particularly with solvent, monomer and catalyst feed, and adverselyaffect catalyst activity and stability. Such impurities may result indecreasing, or even elimination, of catalytic activity, for example. Thepolar impurities or catalyst poisons may include water, oxygen and metalimpurities, for example.

The scavenging compound may include an excess of the aluminum containingcompounds described above, or may be additional known organometalliccompounds, such as Group 13 organometallic compounds. For example, thescavenging compounds may include triethyl aluminum (TMA), triisobutylaluminum (TIBAl), methylalumoxane (MAO), isobutyl aluminoxane andtri-n-octyl aluminum. In one specific embodiment, the scavengingcompound is TIBAl.

In one embodiment, the amount of scavenging compound is minimized duringpolymerization to that amount effective to enhance activity and avoidedaltogether if the feeds and polymerization medium may be sufficientlyfree of impurities.

Polymerization Processes

As indicated elsewhere herein, catalyst systems are used to formpolyolefin compositions. Once the catalyst system is prepared, asdescribed above and/or as known to one skilled in the art, a variety ofprocesses may be carried out using that composition. The equipment,process conditions, reactants, additives and other materials used inpolymerization processes will vary in a given process, depending on thedesired composition and properties of the polymer being formed. Suchprocesses may include solution phase, gas phase, slurry phase, bulkphase, high pressure processes or combinations thereof, for example.(See, U.S. Pat. No. 5,525,678; U.S. Pat. No. 6,420,580; U.S. Pat. No.6,380,328; U.S. Pat. No. 6,359,072; U.S. Pat. No. 6,346,586; U.S. Pat.No. 6,340,730; U.S. Pat. No. 6,339,134; U.S. Pat. No. 6,300,436; U.S.Pat. No. 6,274,684; U.S. Pat. No. 6,271,323; U.S. Pat. No. 6,248,845;U.S. Pat. No. 6,245,868; U.S. Pat. No. 6,245,705; U.S. Pat. No.6,242,545; U.S. Pat. No. 6,211,105; U.S. Pat. No. 6,207,606; U.S. Pat.No. 6,180,735 and U.S. Pat. No. 6,147,173, which are incorporated byreference herein.)

In certain embodiments, the processes described above generally includepolymerizing one or more olefin monomers to form polymers. The olefinmonomers may include C₂ to C₃₀ olefin monomers, or C₂ to C₁₂ olefinmonomers (e.g., ethylene, propylene, butene, pentene, methylpentene,hexene, octene and decene), for example. The monomers may includeolefinic unsaturated monomers, C₄ to C₁₈ diolefins, conjugated ornonconjugated dienes, polyenes, vinyl monomers and cyclic olefins, forexample. Non-limiting examples of other monomers may include norbornene,nobornadiene, isobutylene, isoprene, vinylbenzocyclobutane, sytrene,alkyl substituted styrene, ethylidene norbornene, dicyclopentadiene andcyclopentene, for example. The formed polymer may include homopolymers,copolymers or terpolymers, for example.

Examples of solution processes are described in U.S. Pat. No. 4,271,060,U.S. Pat. No. 5,001,205, U.S. Pat. No. 5,236,998 and U.S. Pat. No.5,589,555, which are incorporated by reference herein.

One example of a gas phase polymerization process includes a continuouscycle system, wherein a cycling gas stream (otherwise known as a recyclestream or fluidizing medium) is heated in a reactor by heat ofpolymerization. The heat is removed from the cycling gas stream inanother part of the cycle by a cooling system external to the reactor.The cycling gas stream containing one or more monomers may becontinuously cycled through a fluidized bed in the presence of acatalyst under reactive conditions. The cycling gas stream is generallywithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product may be withdrawn from the reactor andfresh monomer may be added to replace the polymerized monomer. Thereactor pressure in a gas phase process may vary from about 100 psig toabout 500 psig, or from about 200 psig to about 400 psig or from about250 psig to about 350 psig, for example. The reactor temperature in agas phase process may vary from about 30° C. to about 120° C., or fromabout 60° C. to about 115° C., or from about 70° C. to about 110° C. orfrom about 70° C. to about 95° C., for example. (see, for example, U.S.Pat. No. 4,543,399; U.S. Pat. No. 4,588,790; U.S. Pat. No. 5,028,670;U.S. Pat. No. 5,317,036; U.S. Pat. No. 5,352,749; U.S. Pat. No.5,405,922; U.S. Pat. No. 5,436,304; U.S. Pat. No. 5,456,471; U.S. Pat.No. 5,462,999; U.S. Pat. No. 5,616,661; U.S. Pat. No. 5,627,242; U.S.Pat. No. 5,665,818; U.S. Pat. No. 5,677,375 and U.S. Pat. No. 5,668,228,which are incorporated by reference herein.)

Slurry phase processes generally include forming a suspension of solid,particulate polymer in a liquid polymerization medium, to which monomersand optionally hydrogen, along with catalyst, are added. The suspension(which may include diluents) may be intermittently or continuouslyremoved from the reactor where the volatile components can be separatedfrom the polymer and recycled, optionally after a distillation, to thereactor. The liquefied diluent employed in the polymerization medium mayinclude a C₃ to C₇ alkane (e.g., hexane or isobutane), for example. Themedium employed is generally liquid under the conditions ofpolymerization and relatively inert. A bulk phase process is similar tothat of a slurry process with the exception that the liquid medium isalso the reactant (e.g., monomer) in a bulk phase process. However, aprocess may be a bulk process, a slurry process or a bulk slurryprocess, for example.

In a specific embodiment, a slurry process or a bulk process may becarried out continuously in one or more loop reactors. The catalyst, asslurry or as a dry free flowing powder, may be injected regularly to thereactor loop, which can itself be filled with circulating slurry ofgrowing polymer particles in a diluent, for example. Optionally,hydrogen may be added to the process, such as for molecular weightcontrol of the resultant polymer. The loop reactor may be maintained ata pressure of from about 27 bar to about 50 bar or from about 35 bar toabout 45 bar and a temperature of from about 38° C. to about 121° C.,for example. Reaction heat may be removed through the loop wall via anymethod known to one skilled in the art, such as via a double-jacketedpipe or heat exchanger, for example.

Alternatively, other types of polymerization processes may be used, suchas stirred reactors in series, parallel or combinations thereof, forexample. Upon removal from the reactor, the polymer may be passed to apolymer recovery system for further processing, such as addition ofadditives and/or extrusion, for example.

For example, the additives may include antistatic agents, slip agents,clarifiers. nucleators, hindered amine light stabilizers or combinationsthereof. The antistatic agents may include glyceryl monostearate (GMS),for example. The slip agents may include calcium stearate, zincstearate, ethylene bis-stearamide (EBS), oleamides and combinationsthereof, for example.

In one or more embodiments, the concentration of slip agent isminimized. For example, the concentration of slip agent may be less thanabout 100 ppm, or less than about 50 ppm or less than about 25 ppm, forexample.

Polymer Product

The polymers (and blends thereof) formed via the processes describedherein may include, but are not limited to, linear low densitypolyethylene, elastomers, plastomers, high density polyethylenes, lowdensity polyethylenes, medium density polyethylenes, polypropylene andpolypropylene copolymers, for example.

Unless otherwise designated herein, all testing methods are the currentmethods at the time of filing.

In one or more embodiments, the polymers include propylene basedpolymers. As used herein, the term “propylene based” is usedinterchangeably with the terms “propylene polymer” or “polypropylene”and refers to a polymer having at least about 50 wt. %, or at leastabout 70 wt. %, or at least about 75 wt. %, or at least about 80 wt. %,or at least about 85 wt. % or at least about 90 wt. % polypropylenerelative to the total weight of polymer, for example.

The propylene based polymers may have a molecular weight distribution(M_(n)/M_(w)) of from about 1.5 to about 20, or from about 2 to about12, for example.

In one or more embodiments, the propylene based polymers may have anarrow molecular weight distribution (M_(w)/M_(n)). As used herein, theterm “narrow molecular weight distribution” refers to a polymer having amolecular weight distribution of from about 1.5 to about 8, or fromabout 2.0 to about 7.5 or from about 2.0 to about 7.0, for example.

The propylene based polymers may have a melting point (T_(m)) (asmeasured by DSC) of at least about 110° C., or from about 115° C. toabout 175° C., for example.

The propylene based polymers may include about 15 wt. % or less, orabout 12 wt. % or less 12, or about 10 wt. % or less, or about 6 wt. %or less, or about 5 wt. % or less or about 4 wt. % or less of xylenesoluble material, for example (as measured by ASTM D5492-06).

The propylene based polymers may have a melt flow rate (MFR) (asmeasured by ASTM D-1238) of from about 0.01 dg/min to about 1000dg/min., or from about 0.01 dg/min. to about 100 dg/min., or of at leastabout 10 dg/min. or from about 15 dg/min. to about 50 dg/min., forexample.

In one or more embodiments, the polymers include polypropylenehomopolymers. Unless otherwise specified, the term “polypropylenehomopolymer refers to propylene homopolymers or those polymers composedprimarily of propylene and limited amounts of other comonomers, such asethylene, wherein the comonomer make up less than about 0.5 wt. % orless than about 0.1 wt. % by weight of polymer, for example.

In one or more embodiments, the polymers include propylene based randomcopolymers. Unless otherwise specified, the term “propylene based randomcopolymer” refers to those copolymers composed primarily of propyleneand an amount of other comonomers, wherein the comonomers form at leastabout 0.5 wt. %, or at least about 0.8 wt. %, or at least about 2 wt. %or from about 0.5 wt. % to about 5.0 wt. % comonomer relative to thetotal weight of polymer, for example. In one or more embodiments, thecomonomer content relative to the total weight of polymer is less thanabout 5.0 wt. % , or less than about 4.0 wt. %, or less than about 3.0wt. % or less than about 2.5 wt. %, for example.

The comonomers may be selected from C₂ to C₁₀ alkenes. For example, thecomonomers may be selected from ethylene, propylene, 1-butene,1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene,4-methyl-1-pentene and combinations thereof. In one specific embodiment,the comonomer includes ethylene. Further, the term “random copolymer”refers to a copolymer formed of macromolecules in which the probabilityof finding a given monomeric unit at any given site in the chain isindependent of the nature of the adjacent units.

In one or more embodiments, the propylene based polymer is formed from ametallocene catalyst.

Product Application

The polymers and blends thereof are useful in applications known to oneskilled in the art, such as forming operations (e.g., film, sheet, pipeand fiber extrusion and co-extrusion as well as blow molding, injectionmolding and rotary molding). Films include blown, oriented or cast filmsformed by extrusion or co-extrusion or by lamination useful as shrinkfilm, cling film, stretch film, sealing films, oriented films, snackpackaging, heavy duty bags, grocery sacks, baked and frozen foodpackaging, medical packaging, industrial liners, and membranes, forexample, in food-contact and non-food contact application. Fibersinclude slit-films, monofilaments, melt spinning, solution spinning andmelt blown fiber operations for use in woven or non-woven form to makesacks, bags, rope, twine, carpet backing, carpet yarns, filters, diaperfabrics, medical garments and geotextiles, for example. Extrudedarticles include medical tubing, wire and cable coatings, sheet,thermoformed sheet, geomembranes and pond liners, for example. Moldedarticles include single and multi-layered constructions in the form ofbottles, tanks, large hollow articles, rigid food containers and toys,for example.

In one or more embodiments, the polymers are utilized in melt processingapplications. For example, the polymers may be utilized to form moldedarticles, such as blow molded articles or injection molded articles.

Melt processing applications generally require processing of a meltedpolymer at high temperatures (e.g., temperatures higher than the meltingtemperature of the polymer). For example, the melt processingapplications may include processing temperatures of at least about 110°C., or at least about 120° C., or at least about 140° C. or from about140° C to about 300° C. In addition, melt processed articles, such asthose utilized for food or medical applications may require subsequentheat treatment. For example, medical and/or food applications mayrequire steam sterilization.

Unfortunately, plate-out and bloom (as described above) are commonlyexperienced when melt processing a variety of polymers. In particular,plate-out and bloom occur frequently when processing polymers atelevated temperatures for extended periods of operation, such as thoseutilized in commercial operation.

However, embodiments of the invention unexpectedly provide forcommercially viable operation with minimal to no plate-out or blooming(as measured by visual inspection). In particular, it has unexpectedlybeen observed that the embodiments described herein (e.g., metallocenepolypropylene, less than 5 wt. % ethylene, less than 5 wt. % xylenesolubles, low comonomer incorporation or combinations thereof) providefor commercially viable operation under conditions identical to thoseutilizing Ziegler-Natta polypropylene experiencing plate-out and/orbloom. For example, the embodiments described herein are capable ofproviding for melt processing operations that are significantly longerthan identical operations absent the embodiments of the invention. Inone or more embodiments, which operated at aggressive conditions (highbarrel (e.g., at least 420° F.) and hot runner temperature (e.g., atleast 480° F.)) intended to induce plate-out, the operations utilizingembodiments of the invention are unexpectedly capable of operation of atleast about 20 hours, or at least about 25 hours, or at least about 30hours, or at least about 35 hours or at least about 40 hours withoutobserved plate-out or bloom. However, operations at commercialconditions utilizing embodiments of the invention are unexpectedlycapable of operation of at least about 100 hours, or at least about 150hours, or at least about 200 hours or at least about 250 hours withoutobserved plate-out or bloom.

In one or more embodiment, the articles are utilized for medical or foodapplications, for example, which may require subsequent heat treatment,such as sterilization, for suitability in its intended application. Forexample, subsequent heat treatment may include heating the articles at atemperature of at least about 120° C. for a time of at least about 30mins. Embodiments of the invention further and unexpectedly provide forsignificant reduction in haze upon subsequent heat treating. Forexample, the haze of the article may be reduced by at least about 20%,or at least about 30%, or at least about 50%, or at least about 80%, orat least about 100%, or at least about 150% or at least about 200%compared to articles absent the heat treatment, for example.

EXAMPLES

Sample A was formed from Polymer A, which is a propylene based randomcopolymer formed from a Ziegler-Natta catalyst having 3.2 wt. % ethyleneand a melt flow rate of 10 dg/min., commercially available as P5M4K-046from Huntsman Chemical.

Sample B was formed from Polymer B, which is a propylene based randomcopolymer formed from a Ziegler-Natta catalyst having 2.2 wt. % ethyleneand a melt flow rate of 10 dg/min., commercially available as 7525MZfrom TOTAL Petrochemicals USA, Inc.

Sample C was formed from Polymer C, which is a propylene based randomcopolymer formed from a metallocene catalyst having 1.5 wt. % to 2.5 wt.% ethylene and having a melt flow rate of 30 dg/min., commerciallyavailable as M6823MZ from TOTAL Petrochemicals USA, Inc.

Sample D was formed from Polymer D, which is a propylene based randomcopolymer formed from a metallocene catalyst having 2.2 wt. % ethylenehaving a melt flow rate of 32 dg/min. and commercially available as6823MZ from TOTAL Petrochemicals USA, Inc.

Sample E was formed from Polymer E, which is a propylene based randomcopolymer formed from a Ziegler-Natta catalyst having 2.7 wt. % ethyleneand having a melt flow rate of 30 dg/min.

Example 1

Polymer articles were formed by injection molding polymer samples toform caps.

Sample A was run at a hot runner temperature of 450° F. and a barreltemperature profile of 400/420/420/450° F. on day 1, hot runnertemperature of 480° F. on days 2-5 and barrel temperature profile of420/440/440/470° F. on day 2, 430/450/450/480° F. on day 3,440/460/460/490° F. on days 4-5. Plate-out began on day 4 and turnedsignificantly severe (enough plate out to cease operation) on day 5.

Sample B was run at a hot runner temperature of 480° F. and a barreltemperature profile of 440/460/460/49020 F. for 5 days. Plate-out beganon day 4 and turned significantly severe (enough plate out to ceaseoperation) on day 5.

Sample C was run at a hot runner temperature of 480° F. and a barreltemperature profile of 440/460/460/490° F. for 5 days. No plate-out wasobserved.

Sample D was run at a hot runner temperature of 480° F. and a barreltemperature profile of 440/460/460/490° F. for 5 days. No plate-out wasobserved.

It was observed that Samples C and D exhibited significantly longeroperation times than Samples A and B with no plate-out observed.

Example 2

Polymer articles were heat treated at 120° C. for 30 minutes andproperties of the article were then measured. The properties of the heattreated articles and non-heat treated articles (labeled as control)follow in Table 1.

TABLE 1 Haze (0.02″ Haze (0.04″ Haze (0.06″ Haze (0.08″ Samplethickness) thickness) thickness) thickness) C (control) 4.88 9.23 15.719.1 C 4.24 8.75 15.4 18.7 E (control) 7.99 19.7 32.5 43.8 E 28.6 35.843.9 53.6 *haze is measured by ASTM D-1003

It was observed that Sample C exhibited much less increase in haze(actually a decrease in haze) upon heating compared to Sample E (whichexhibited at least 20% increase and as much as 250%).

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof and the scope thereof isdetermined by the claims that follow.

1. A process of forming polymer articles comprising: providing apropylene based polymer formed from a metallocene catalyst; meltprocessing the propylene based polymer to form a polymer article,wherein the process is capable of operation for at least about 30 hoursat a barrel temperature of at least 420° F. and a hot runner temperatureof 480° F. without experiencing plate-out.
 2. The process of claim 1further comprising contacting the propylene based polymer with anadditive selected from the antistatic agents, slip agents, clarifiers,nucleators, hindered amine light stabilizers and a combinations thereof.3. The process of claim 2, wherein the propylene based polymer iscontacted with less than about 100 ppm slip agent.
 4. The process ofclaim 1, wherein the propylene based polymer exhibits a molecular weightdistribution of from about 1.5 to about
 12. 5. The process of claim 1,wherein the propylene based polymer exhibits a molecular weightdistribution of from about 1.5 to about
 8. 6. The process of claim 5wherein the molecular weight distribution is attained without the use ofperoxides.
 7. The process of claim 1 further comprising heat treatingthe polymer article, wherein the polymer article at least maintains hazeupon heat treating at 120° C. for 30 minutes.
 8. The process of claim 1,wherein the propylene based polymer comprises less than about 5 wt. %xylene solubles.
 9. The process of claim 1, wherein the propylene basedpolymer exhibits a melt flow rate of from about 15 dg/min. to about 100dg/min.
 10. The process of claim 1, wherein the propylene based polymerexhibits a melt flow rate of from about 15 dg/min. to about 50 dg/min.11. The process of claim 1, wherein the propylene based polymer isformed with low co-monomer incorporation.
 12. The process of claim 1,wherein the melt processing occurs at a temperature of at least about110° C.
 13. A polymer article formed from the process of claim
 1. 14.The polymer article of claim 11 for use in medical or food applications.15. The process of claim 1, wherein the propylene based polymercomprises a random copolymer.
 16. The process of claim 15, wherein therandom copolymer comprises less than about 5.0 wt. % ethylene relativeto the total weight of random copolymer.
 17. A process of formingpolymer articles comprising: providing a propylene based random polymerformed from a metallocene catalyst, wherein the propylene based randomcopolymer comprises from about 0.5 wt. % ethylene and exhibits a meltflow rate of from about 15 dg/min. to about 100 dg/min.; melt processingthe propylene based polymer to form a polymer article; and heat treatingthe polymer article, wherein the polymer article exhibits a reduction inhaze upon heat treatment.
 18. The process of claim 17, wherein thepropylene based polymer exhibits a melt flow rate of from about 15dg/min. to about 50 dg/min.